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महाराष्ट्र राज्य शिक्षण मंडळएचएससी विज्ञान (सामान्य) इयत्ता १२ वी

Explain the following reaction with a suitable example. Hofmann elimination reaction - Chemistry

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प्रश्न

Explain the following reaction with a suitable example.

Hofmann elimination reaction

दीर्घउत्तर
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उत्तर

  1. When tetraalkylammonium halide is heated with moist silver oxide, it gives quaternary ammonium hydroxide.
  2. Quaternary ammonium hydroxides on strong heating undergo β-elimination to give an alkene. This reaction is called Hofmann elimination.
  3. The least substituted alkene is obtained as a major product (in contrast to Saytzeff elimination).
    e.g. Hofmann elimination reaction of N, N, N-Triethylpropylammonium iodide
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पाठ 13: Amines - Long answer questions

संबंधित प्रश्‍न

How is ethyl amine prepared from methyl iodide?


Identify the compounds 'A' and 'B' in the following equation:


Write the chemical equation involved in the following reaction:

Hoffmann-bromamide degradation reaction


Write a short note on the following:

Hoffmann’s bromamide reaction


Give the structure of A, B and C in the following reaction:

\[\ce{CH3CH2I ->[NaCN] A ->[OH-][Partial hydrolysis] B ->[NaOH + Br2] C}\]


Give the structure of A, B and C in the following reaction:

\[\ce{C6H5NO2 ->[Fe/HCl] A ->[NaNO2 + HCl][273 K] B ->[H2O/H+][\Delta] C}\]


Write the reaction of aromatic primary amine with nitrous acid.


Identify 'A' and 'B' in the following reaction and rewrite the complete reaction :


Arrange the following in the increasing order of their pKvalues:

C6H5NH2, C2H5NH2, C6H5NHCH3


Give the structures of A, B and C in the following reactions :


Give the structures of A, B and C in the following reactions :


Give the structures of A, B and C in the following reactions :


Account for the following:
Gabriel phthalimide synthesis is not preferred for preparing aromatic primary amines.


Answer in one sentence.

Predict the product of the following reaction.

\[\ce{Nitrobenzene ->[Sn/conc.HCl]?}\]


Answer the following

Identify A and B in the following reactions.

\[\ce{C6H5CH2Br->[alco.][KCN]A ->[Na/ethanol]B.}\]


Write reactions to prepare ethanamine from Acetonitrile.


Name the process of breaking C-X bond by ammonia in preparation of amines.


Explain Hoffmann’s exhaustive alkylation with suitable reactions.


Identify compound 'B' in following series of reactions?

\[\ce{Acetonitrile ->[Na/alcohol] A ->[NaNO2/dil.HCI] B}\]


____________ can be prepared exclusively by Gabriel phthalimide synthesis.


What product is formed when \[\ce{R - C ≡ N}\] is hydrolysed?


What is the molar mass of the amine formed when acetamide undergoes Hofmann bromamide degradation?


Which of the following reactions is appropriate for converting benzamide to aniline?


Identify the product obtained when benzamide is treated with bromine and aqueous sodium hydroxide?


The reduction of alkyl cyanide with sodium and ethanol to give primary amines is, ____________.


Identify the INCORRECT statement regarding Hofmann bromamide reaction.


In aqueous phase the order of basic strength of alkylamine is ______.


Which of the following reagents is used in Hofmann's elimination reaction of amines?


Which of the following does NOT give carbylamine test?


Which of the following reactions does NOT yield an amine?


Which of the following reagents would not be a good choice for reducing an aryl nitro compound to an amine?


In order to prepare a 1° amine from an alkyl halide with simultaneous addition of one \[\ce{CH2}\] group in the carbon chain, the reagent used as source of nitrogen is ______.


Amongst the given set of reactants, the most appropriate for preparing 2° amine is ______.


Which of the following compounds is the weakest Brönsted base?


The reagents that can be used to convert benzenediazonium chloride to benzene are:

(i) \[\ce{SnCl2/HCl}\]

(ii) \[\ce{CH3CH2OH}\]

(iii) \[\ce{H3PO2}\]

(iv) \[\ce{LiAlH4}\]


Which of the following amines can be prepared by Gabriel synthesis.

(i) Isobutyl amine

(ii) 2-Phenylethylamine

(iii) N-methylbenzylamine

(iv) Aniline


Identify A and B in the following reaction.


Write following conversions:

acetanilide `->` p-nitroaniline


How will you carry out the following conversion?


Account for the following:

Aniline cannot be prepared by the ammonolysis of chlorobenzene under normal conditions.


A primary amine is formed by an amide on treatment with bromine and alkali. The primary amine has


The compound X is which of the following?

\[\ce{CH3CN ->[Na + C2H5OH] x}\]


Reduction of nitro alkanes yields which compound?


C6H5CONHCH3 can be converted into C6H5CH2NHCH3 by:-


When primary amines are treated with HCl, the product obtained is which of the following?


Which of the following CANNOT be prepared by ammonolysis of alkyl halide?


A compound 'A' on reduction with iron scrap and hydrochloric acid gives compound 'B' with molecular formula C6H7N. Compound 'B' on reaction with CHCl3 and alcoholic KOH produces an obnoxious smell of carbylamine due to the formation of 'C'. Identify 'A', 'B' and 'C' and write the chemical reactions involved.


Which of the following compound gives pink colour on reaction with phthalic anhydride in cone. H2SO4 followed by treatment with NaOH?


The amine 'A' when treated with nitrous acid gives yellow oily substance. The amine A is ______.


Which of the following statement(s) is/are incorrect in case of Hofmann bromamide degradation?


Amides can be converted into amines by the reaction named ______.


Identify A and B in the following reaction.

\[\ce{C6H5CH2Br ->[Alco.][KCN] A ->[Na/Ethanol][reduction] B}\]


Write a short note on the following:

Ammonolysis


Write the name of reduction product formed when ethyl cyanide is treated with sodium and alcohol.


Write short note on the following:

Ammonolysis


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